Shockwave mitigation system for supersonic aircraft

ABSTRACT

A method of supersonic thrust generation includes generating a thrust supersonic exhaust plume having a first average velocity from an engine, and expelling a bypass exhaust plume having a second average velocity from the engine, the first average velocity greater than the second average velocity, so that the bypass exhaust plume inhibits coalescence of an engine exhaust plume compression shockwave.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. patentapplication Ser. No. 14/272,908 filed Sep. 22, 2016, which claimspriority to and the benefit of U.S. Provisional Patent Application No.62/222,074 filed Sep. 22, 2015, the contents of which are incorporatedby reference herein for all purposes.

BACKGROUND Field of the Invention

The field of the invention relates to supersonic aircraft structures,and more particularly systems to mitigate sonic ground effects of suchaircraft.

Description of the Related Art

Government agencies administer policies on noise limits for civilsupersonic aircraft that are intended to protect the public fromexcessive and environmentally damaging noise pollution caused byearthward propagating compression shockwaves (i.e., sonic booms) fromsuch aircraft. For example, since March 1973, supersonic flight overland by civil aircraft has been prohibited in the United States. Pastefforts at mitigating such sonic booms include attempts at re-shaping orreducing the peak intensity of such compression shockwaves impacting atground level, such as Gulfstream's “spike” that transforms thetraditional N-wave sonic boom into a smooth and more rounded pressurewave shaped roughly like a sine wave or sideways “S”. (FederalRegister/Vol. 76, No. 100/Tuesday, May 24, 2011/Notices P. 30231).

There has been a long and unmet need for civil supersonic airtransportation in many countries. The National Aeronautics and SpaceAdministration in the United States projects that supersonic flight overland may result in a 50% reduction in cross country travel time,facilitate movement of time-critical cargo, including life-savingmedical supplies, and enhance homeland security through rapidtransportation of critical responder teams. (Fixing the Sound BarrierThree Generations of U.S. Research into Sonic Boom Reduction . . . andwhat it means to the future. FAA Public Meeting on Sonic Boom. Jul. 14,2011(http://www.faa.gov/about/office_org/headquarters_offices/apl/noise_emissions/supersonic_aircraft_noise/media/NASA %20Presentation.pdf, accessed Sep. 16, 2016)Without significant reduction in compression shockwave energy receivedat ground level, supersonic flight by civil aircraft over land will notbecome a reality in most countries.

A need continues to exist to reduce the peak intensity of sonic boomsreaching the ground, or to eliminate them entirely, for aircraft flyinggreater than the speed of sound.

SUMMARY

A method of shock wave mitigation in supersonic vehicles may includegenerating an earthward propagating wing compression shockwave from acurved wing, expelling a first supersonic exhaust plume having a firstaverage velocity from an engine, the engine having an engine housing,reflecting a majority of the earthward propagating wing compressionshockwave back towards the curved wing using the engine (see below forengine casing reflection vs. thrust reflection), expelling a bypassexhaust plume having a second average velocity adjacent to the firstsupersonic exhaust plume, the second average velocity being slower thanthe first average velocity, and inhibiting coalescence of an engineexhaust plume compression shockwave extending from the first supersonicexhaust plume using the bypass exhaust plume. The step of reflecting amajority of the earthward propagating wing compression shockwave backtowards the curved wing using the engine may further include reflectingthe wing compression shockwave off of the engine housing. The method mayalso include moving the engine housing to meet the wing compressionshockwave, and the step of moving the engine housing may includetranslating the engine along the axis of freestream air flow about theengine. In some embodiments, the method may include slidably moving thewing relative to a fuselage that is itself slidably coupled to the wingso that the wing compression shockwave is moved relative to the engineto meet the engine housing for reflection. In other embodiments,reflecting a majority of the wing compression shockwave back away fromthe earth may also include reflecting the wing compression shockwave offof the first supersonic exhaust plume. The reflection of the wingcompression shockwave off of the first supersonic exhaust plume mayestablish an upward propagating reflected compression shockwave. Thesecond average velocity (of the bypass exhaust plume) may beapproximately the same velocity as a freestream velocity about the wing.In certain embodiments, the bypass exhaust plume is expelled from theengine, and the bypass exhaust plume may include air sourced from (i)bleed air taps from a compressor in the engine or (ii) bleed air taps atinlet shock ramps disposed at a front of the engine. In certainembodiments of the engine, the engine may have a first nozzle expellingthe first supersonic exhaust plume and a second nozzle expelling abypass exhaust plume that has an average velocity that is slower than anaverage velocity of the first supersonic exhaust plume. The wing mayhave a bottom surface shape configured to direct the compressionshockwave toward the engine. The step of generating a downwardpropagating wing compression shockwave from the curved wing towards theearth may include propagating a majority or substantially all of thecompression shockwave toward a rear portion of the engine housing. Inother embodiments, generating a downward propagating wing compressionshockwave from the curved wing towards the earth comprises propagatingsubstantially all of the compression shockwave toward the firstsupersonic exhaust plume. The curved wing may have an outboard portionshape that is straight or upward curving so that a high-pressureunderwing to freestream low pressure interface channels a soundpropagating vector that is at an inclination to the ground and parallelto the ground, respectively. The engine may be selected from the groupconsisting of a jet engine, turbojet engine, ramjet engine, scramjetengine, high bypass turbojet, variable cycle engine, and adaptive-cycleengine. In other embodiments, less than the entire wing compressionshockwave is reflected back towards the curved wing using the engine.

A method of supersonic thrust generation includes generating a thrustsupersonic exhaust plume having a first average velocity from an engine,and expelling a bypass exhaust plume having a second average velocityfrom the engine, the first average velocity greater than the secondaverage velocity. The thrust supersonic exhaust plume and bypass exhaustplume may be substantially aligned when exiting the engine. The bypassexhaust plume may be generated from a source selected from the groupconsisting of (i) bleed air taps from a compressor in the engine, (ii)bleed air taps at inlet shock ramps disposed at a front of the engine.

An air vehicle may include a fuselage, an engine comprising an exhaustplume nozzle, a bypass plume nozzle disposed adjacent to the exhaustplume nozzle, and a curved supersonic wing coupled to the fuselage, thecurved supersonic wing curving about the engine. The engine may alsoinclude the bypass plume nozzle rather than apart from the engine. Theengine may be translatable in relation to the curved supersonic wing. Inan alternative embodiment, the curved supersonic wing may betranslatable in relation to the engine. The air vehicle may also includean engine casing disposed on the engine, the engine have a wing-facingcurved portion that has a center of radius that substantially coincideswith a center of radius of an underside of the curved supersonic wing. Aplurality of control surfaces may also be included, the control surfacesnot operable to extend downwards during supersonic flight. In otherembodiments, an engine casing is coupled to the engine, the enginecasing having a flat bottom portion that is in a plane parallel tofreestream air flow when such freestream air flow is greater than Mach 1during flight. The engine may be operable to provide supersonic thrustthrough the exhaust plume nozzle that has an average supersonic velocitythat is greater than a supersonic velocity provided through the bypassplume nozzle.

A method of shock wave mitigation in supersonic vehicles may includegenerating an earthward propagating wing compression wave region from acurved wing, expelling a first supersonic exhaust plume having a firstaverage velocity from an engine, the engine having an engine housing,and translating the engine to expel the first supersonic exhaust plumeimmediately upstream from the earthward propagating wing compressionwave region, wherein the earthward propagating wing compression waveregion is inhibited from coalescing into a compression shockwave by thefirst supersonic exhaust plume. The method may also include expelling abypass exhaust plume having a second average velocity adjacent to thefirst supersonic exhaust plume, the second average velocity of thebypass exhaust plume being slower than the first average velocity of thefirst supersonic exhaust plume, and inhibiting coalescence of an engineexhaust plume compression shockwave extending from the first supersonicexhaust plume using the bypass exhaust plume.

BRIEF DESCRIPTION OF THE DRAWINGS

The components in the figures are not necessarily to scale, emphasisinstead being placed upon illustrating the principals of the invention.Like reference numerals designate corresponding parts throughout thedifferent views. Embodiments are illustrated by way of example and notlimitation in the figures of the accompanying drawings, in which:

FIGS. 1 and 2 are front and top plan reviews, respectively, of oneembodiment of a supersonic aircraft having two curved wings to directearthward propagating wing compression waves to respective bifurcatedexhaust engines for compression wave mitigation;

FIGS. 3 and 4 are rear plan views illustrating two implementations of abifurcated exhaust engine;

FIG. 5 illustrates one embodiment of a bifurcated exhaust engine havinga single turbojet engine and using a bypass exhaust plume to inhibitcoalescence of an engine exhaust plume compression shockwave;

FIGS. 6-10 are rear plan views illustrating alternative implementationsof a bifurcated exhaust engine;

FIG. 11 illustrates another embodiments of a bifurcated exhaust enginehaving two turbojet engines and using a bypass exhaust plume to inhibitcoalescence of an engine exhaust plume compression shockwave

FIG. 12 illustrates an engine that is operable to translate in relationto a supersonic wing to enable reflection of an earthward propagatingwing compression shockwave back up and away from ground; and

FIGS. 13, 14 and 15 illustrate different embodiments of a curved wingand bifurcated engine, with respective wings having concave, straightand convex outboard wing portions.

DETAILED DESCRIPTION

A bifurcated exhaust engine and wing configuration are disclosed thatare operable to inhibit coalescence of any supersonic exhaust plumecompression shockwave and that are capable of reflecting an earthwardpropagating wing compression shockwave back up and away from the groundto eliminate or substantially reduce transmission of sonic booms toground level for aircraft flying greater than the speed of sound.

FIGS. 1 and 2 are front and top plan reviews, respectively, of asupersonic aircraft having a fuselage coupled between two curvedsupersonic wings, and respective engines that are positioned tointercept and reflect earthward propagating wing compression shockwaves,with the engines also designed to mitigate exhaust plume compressionshockwaves. Each of the curved supersonic wings 102 may be attached tothe fuselage 104 in a high-wing configuration, with each engine 106connected underneath to its respective wing 102 through an engine pylon108 to provide supersonic thrust for propulsion of the supersonicaircraft 100. Each engine 106 may be positioned with an engine outlet110 terminating in front of a respective wing compressive lift shockregion 112 that provides lift to the curved wing 102 during supersonicflight. Each engine 106 is preferably slidably coupled to its respectivecurved supersonic wing 102 to enable roll axis linear translation from afore engine position to an aft engine position (see FIGS. 11 and 12). Inan alternative environment, each engine 106 is capable oftwo-dimensional translational movement, such as a linear translationalong the roll axis and along the yaw axis. Such capability would alloweach engine outlet 110 (otherwise referred to as “nozzles”), to movecloser to or further away from its adjacent wing compressive lift shockregion 112, or closer to or further from the underside 114 of eachrespective wing 102. In an alternative embodiment, each engine 106 maybe slidably coupled to the fuselage 104, rather than to the wing 102, toenable translation along the roll and or yaw axis of each engine 106with respect to its associated wing 102. An engine casing 118 may beslidably or fixedly coupled to the engine 106 and disposed on andencompassing a rear portion of each engine 106. The engine casings 118may each have a wing-facing curved portion for receipt of an earthwardpropagating wing compression shockwave (indicated by dashed arrows). Inone embodiment, each engine casing 118 has a center of radius R_(H)having a center point C that substantially coincides with a center pointC of a radius R_(W) of an underside of the curved supersonic wing 102.

Each of the curved supersonic wings 102 may be formed in a curvedanhedral or curved dihedral spanwise configuration, with the engines 106generally centered at a respective center of radius for each of thecurved lower surfaces of the wings. During supersonic flight, eachcurved wing 102 generates an earthward propagating wing compressionshockwave that is directed toward an aft portion of its associatedengine casing 118 or its associated supersonic exhaust plume (see FIG.5). In embodiments using engines 106 that are operable to translate foreand aft, the engines 106 may translate to more closely match movement ofthe earthward propagating wing compression shockwave as it translateswith varied supersonic aircraftspeeds. In further embodiments, the wings102 may be slidably coupled to the fuselage 104 to enable variabledisplacement between the engines 106 and respective wings 102 should theearthward propagating wing compression shockwave translate fore or aftwith aircraft speed. The wing planforms may be rectangular or delta ormay consist of another planform deemed desirable for supersonic flight.

In the illustrated embodiment, the supersonic aircraft has a verticalstabilizer 120 and two aft mounted control surfaces 122 for pitch androll control. The control surfaces 122 are not operable to extenddownwards during supersonic flight so as to avoid additional earthwardpropagating compression shockwaves. The fuselage 104 is flat-bottomedand configured with the two wings 102 to be parallel to the freestreamair flow during supersonic flight to reduce the possibility ofunintended compression shockwave formation propagating earthward duringupright flight.

FIGS. 3 and 4 are rear plan views illustrating two implementations of abifurcated exhaust engine having an engine casing positioned to receivean earthward propagating wing compression shockwave from a curvedsupersonic wing 102. The engines (300, 402) may be located atapproximately a center of radius C of the underside of the curvedsupersonic wing 304. In FIG. 3, an outer surface of the engine casing306 is substantially cylindrical at the anticipated point of reflectionof the wing compression shockwave, and is configured in complementaryopposition to an underside 308 of the curved wing 102 such that anearthward propagating wing compression shockwave 310 emanating from thecurved wing 102 is reflected by the engine casing 306 back to the curvedwing 304 within the illustrated plane of the figure. In FIG. 4, anengine casing 402 does not have a spherical upper surface and so not allof an earthward propagating wing compression shockwave 404 is reflectedback to the curved wing 304. However, the engine casing 402 is shaped atthe anticipated point of reflection such that a majority of theshockwave is reflected back towards the curved wing 304 (i.e., using theengine) and substantially none of the shockwave is directed towards theground during level flight of the aircraft.

High speed and low speed engine exhaust regions may be provided in thebifurcated exhaust engine, with an upper exhaust plume nozzle (312, 406)providing the high speed exhaust region and the adjacent lower bypassplume nozzle (314, 408) providing the low speed engine exhaust region.As used herein, “high speed” and “low speed” are intended to indicaterelative speed between them, rather than absolute speed values. Forexample, a high speed average flow exiting the upper exhaust plumenozzle may be Mach 1.0-4.0, while a “low speed” average flow exitinglower bypass plume nozzle may be Mach 0.9-2.5, so long as the high speedaverage velocity is higher than the low speed average velocity at anypoint in time. As used herein, “higher” and “lower” are also relativepositions having a reference frame of an aircraft that is upright andrelatively level with respect to the Ground. In FIG. 3, the enginecasing has a substantially circular cross section and is parallel to thefree stream at an anticipated area of reflection of the wing compressionshockwave 310 to provide more complete reflection back to the curvedwing 102. Each of the high and low speed exhaust plume nozzles (312,314) may be truncated at their exit planes and not wholly circular, suchas to form semicircles at their exit planes. In FIG. 4, each of the highand low speed exhaust plume nozzles (406, 408) are substantiallycircular at their exit planes and the engine casing 410 may besubstantially ellipsoid and parallel to the free stream at theanticipated area of shockwave reflection.

FIG. 5 depicts a bifurcated exhaust engine that expels a bypass exhaustplume to inhibit coalescence of an engine exhaust plume compressionshockwave, and to reflect an earthward propagating wing compressionshockwave that is reflected off an engine housing of the bifurcatedengine. The engine, illustrated as a turbojet engine 500, may have aninlet cone or dual inlet ramps (502, 504) that may be disposed in frontof and between an upper thrust air intake 506 and lower bypass airintake 508. Upper and lower oblique shock waves (510, 512) may form atthe dual inlet ramps (502, 504) at free stream air speeds of greaterthan Mach 1. The upper thrust air intake 506 leads to a subsonicdiffuser section 514 that delivers subsonic air to a compression section516, with the compressed air then delivered to a combustion chamber 518for mixing with a fuel, combustion, and hence to a turbine section 520for expansion of the resultant gases out of a nozzle section to expel asupersonic exhaust plume 522.

The lower oblique shockwave 512 may be reflected internally within thelower bypass air intake 508 before producing a normal shockwave 524immediately in front of a subsonic flow region 526. The subsonic flowregion 526 receives the resulting high-pressure air. Bleed air may beprovided to the subsonic flow region 526, such as from bleed air taps528 leading from the compression section 516, from the inlet shock ramps(502, 504), or from the upper supersonic exhaust plume 522 (before itexits its respective nozzle) using direct ducting of the exhaust thathas been slowed to ‘near free stream’ velocity. The high-pressured airmay then be presented to a bypass throat 528 for expulsion from a secondnozzle section 530 as a bypass exhaust plume 532, with the second nozzlesection 530. The bypass exhaust plume 532 has an average speed that isslower than the supersonic speed of the supersonic exhaust plume 522.Although the actual velocity of the bypass exhaust plume 532 may begreater than, equal to, or less than Mach 1.0 when expelled from thesecond nozzle, its relative velocity to the free stream 534 is subsonic(M<1.0) to avoid transmittal shock to the free stream 534 upon contactwith it during supersonic flight. A shockwave front 536 that wouldotherwise exist from the supersonic exhaust plume 522 is abated inresponse to freestream contact with the bypass exhaust plume 532.

The engine 500 may have an engine housing 538 having a top cylindricalsurface or otherwise curved exterior surface that is parallel to thefree stream air 534 to prevent generation of a compression shock wave.An earthward propagating wing compression shockwave 540 is illustratedextending down and reflecting off of the engine housing 538 duringnormal flight to reflect a majority, or as illustrated, “all,” of theearthward propagating wing compression shockwave 540 back towards thecurved wing (see FIG. 1). The supersonic exhaust plume 522 is deflecteddown due to pressure 542 behind the reflected wing compression shockwave540, with the deflected supersonic exhaust plume 522 causing a similardeflection downward of the bypass exhaust plume 532. Because the bypassexhaust plume 532 is at a relative velocity that is subsonic (M<1.0)with respect to the free stream 534, coalescence of an engine exhaustplume compression shockwave 536 is inhibited.

FIGS. 6-10 are rear plan views illustrating different embodiments of abifurcated exhaust engine that may be used to inhibit coalescence of anengine exhaust plume compression shockwave, and to reflect an earthwardpropagating wing compression shockwave. More particularly, FIG. 6illustrates a bifurcated exhaust engine 600 having an upper exhaustplume nozzle 602 and a lower bypass plume nozzle 604. The engine casing606 encompassing both nozzles (600, 602) is substantially circular incross section, with both the upper exhaust plume nozzle 602 and lowerbypass plume nozzle 604 both having substantially a semi-circular crosssection at their exit planes. In another embodiment illustrated in FIG.7, the entirety of the engine casing 700 is not semicircular in crosssection, but rather may form a flat lower portion such as a flat lowersurface 702 underneath the lower bypass plume nozzle 604. The enginecasing 700 may have sidewalls (704, 706) extending down from either sideof the semi-circular upper surface 708. The upper exhaust plume nozzle602 and lower bypass plume nozzle 604 may each have a semi-circularcross section as in FIG. 6. In FIG. 8, the engine casing may take theform of two separate engine casings, with the upper engine casing 800encompassing the upper exhaust plume nozzle 802 and the lower enginecasing 804 encompassing the lower bypass plume nozzle 806. In FIG. 9,the engine casing 900 has upper and lower semicircular exterior Surfaces(902, 904) and side panels (906, 908) extending between the upper andlower semicircular exterior surfaces (902, 904) and encompassing theupper exhaust plume nozzle 802 and lower bypass plume nozzle 806. InFIG. 10, the engine casing 1000 may have a semicircular upper reflectingsurface 1002, a flat lower surface 1004 and side panels (1006, 1008)encompassing the upper exhaust plume and lower bypass plume nozzles.

It may be understood that the described engine casings need not have thesame cross section in the longitudinal direction (i.e., in thefore-to-aft aircraft dimension). Rather, the outer engine casing mayhave a shape that maintains an upper and lower orientation of theexhaust plume nozzle and a lower bypass plume nozzle, respectively, andmay maintain a pre-determined upper reflecting surface at theanticipated area of compression shockwave reflection. Also, although theengine casings are illustrated as substantially semicircular orcircular, they may be formed in other shapes, including elliptical andrectangular, and may be independent from the supersonic nozzle shape.For example, the engine casings illustrated in FIGS. 6-10 may eachencompass bell-shaped nozzles, plug nozzles, variable flap ejectornozzles, aerospike engines, expanding nozzles or other nozzles thataccomplish the task of supersonic flight with the low speed engineexhaust region having a relative subsonic velocity with the free stream.

FIG. 11 depicts a bifurcated exhaust engine that has upper and lowerengines producing an upper thrust exhaust plume and lower bypass exhaustplume, respectively, with the lower bypass exhaust plume having anaverage velocity that is subsonic relative to a free stream. In oneembodiment, the engines are upper and lower turbojet engines (1100,1102). Upper and lower subsonic diffuser sections (1104, 1106) deliversubsonic air to respective compression sections (1108, 1110), with thecompressed air then delivered to respective combustion chambers (1112,1114) for mixing with a fuel, combustion, and hence to respectiveturbine sections (1116, 1118) for expansion of the resultant gasesresulting in an upper supersonic exhaust plume 1120 and bypass exhaustplume 1122. With such a configuration, bleed air may not be collectedfrom bleed air taps, but rather the bypass exhaust plume is generatedfrom the lower turbojet engine 1102 itself. Similar to the embodimentillustrated in FIG. 5, an earthward propagating wing compressionshockwave 540 is illustrated extending down and reflecting off of theengine housing 1124 during normal flight to reflect a majority, or asillustrated, “all,” of the earthward propagating wing compressionshockwave 540 back towards the curved wing (see FIG. 1). The supersonicexhaust plume 1120 is deflected down due to pressure 542 behind thereflected wing compression shockwave 540, with the deflected supersonicexhaust plume 1120 causing a similar deflection downward of the bypassexhaust plume 1122 to inhibit coalescence of an engine exhaust plumecompression shockwave 1126 that would extend from the first supersonicexhaust plume.

FIGS. 12 and 13 illustrate a side plan view of an engine that isoperable to translate along the axis of freestream air flow to meet awing compression shockwave for subsequent reflection back up and awayfrom ground. A supersonic wing 1200 and engine, such as a turbojetengine 1204, are configured to be movable in relation to one another.For example, the supersonic wing 1200 and turbojet engine 1204 may beslidably coupled together, such as through an engine pylon with asliding mechanism. In other embodiments, the turbojet engine 1204 may beslidably coupled to a fuselage (not shown) that is itself fixedlycoupled to the wing 1200, or the wing 1200 may be slidably coupled tothe fuselage with the fuselage fixedly coupled to the turbojet engine1204. In any of the described configurations, an engine casing 1206encompassing at least a portion of the turbojet engine 1204 isillustrated initially positioned in a fore position to intercept anearthward propagating wing compression shockwave 1208 extending from thesupersonic wing 1200. The earthward propagating wing compressionshockwave 1208 is illustrated as extending approximately perpendicularlyfrom a leading edge 1210 of the supersonic wing 1200 relative to a freestream supersonic flow 1212 having a first velocity, such as Mach 1.0.As a speed of the free stream supersonic flow 1212 increases, such asapproaching Mach 1.4, the earthward propagating wing compressionshockwave 1208′ may begin to extend back from perpendicular and awayfrom the turbojet engine 1204. In one embodiment, the turbojet engine1204 may be linearly translated to position 1204′ concurrently withrearward movement of the shockwave 1208′ so that the earthwardpropagating wing compression shockwave 1208′ continues to impinge on theengine casing 1206 for reflection. Similarly, as the free stream airflowcontinues to increase in velocity, such as to Mach 1.8 and, onward toMach 2.2, the position of the earthward propagating wing compressionshockwave may continue to move (1208″, 1208′) and the turbojet engine1204 translated concurrently to intermediate position 1204″ and aftposition 1204′, respectively, to enable all or nearly all of theearthward propagating wing compression shockwave to reflect off of theengine casing 1206. In other embodiments, the turbojet engine is abifurcated exhaust engine and the bifurcated exhaust engine istranslated in accordance with the scheme described, above.

In an alternative embodiment, the engine casing 1206 or other outersurface is operable to translate independently, or in addition to,translation of the engine 1204 to meet the earthward propagating wingcompression shockwave. In such an embodiment, reference numerals 1204′,1204″ and 1204′″ may represent only the engine casing 1206 or otherouter surface, and a majority of the engine 1204 may remainsubstantially fixed to the wing or fuselage. For example, the wing 1200may remain fixed with respect to the engine 1206, but the engine casing1206 may extend along the axis of freestream air flow to meet theshockwave (1208, 1208′, 1208″, 1208′) for subsequent reflection back upand away from ground. In a further embodiment, the engine 1204 moveswith respect to the wing 1200 and the engine casing (or other outersurface) is operable to move with respect to the engine 1204 to extendalong the axis of freestream air flow to enable the engine casing (orother outer surface) to meet the earthward propagating wing compressionshockwave. Such translation capability of the engine 1204 and/or enginecasing 1206 may enable to expulsion of the first supersonic exhaustplume immediately upstream from the earthward propagating wingcompression wave region to eliminate or substantially reducetransmission of sonic booms to ground level for aircraft flying greaterthan the speed of sound.

FIGS. 13, 14, and 15 are rear plan views illustrating starboardsupersonic curved wings in a dihedral configuration, and associatedengine nozzles, with the curved wings having outboard portion shapesthat are concave, straight and convex (i.e., upward curving),respectively. During supersonic flight, high pressure areas (1300, 1400,1500) may exist underneath respective curved wings (1302, 1402, 1502).Pressure gradients (1304, 1404, 1504) will develop that extend from suchhigh pressure areas (1300, 1400, 1500) to the freestream adjacent wingtips (1306, 1406, 1506) of each wing. Such pressure gradients (1304,1404, 1504) may not be sufficient to generate a compression shockwaveperpendicular to the direction of flight. However, they may result inpropagation of a resulting pressure wave, as guided by an underside(1308, 1408, 1508) of each respective wing, that is analogous to amegaphone directing sound. The sound will tend to fall off away from acenterline (1310, 1410, 1510) of such a pressure gradient. Asillustrated in the different wing configurations of FIGS. 13-15, thecenterline (otherwise referred to as a “datum line” or “soundpropagating vector”) may extend an angle (ø) from ground during levelflight depending on the configuration of the outboard wing portions. InFIG. 14, the straight outboard wing portion 1412 (indicated with dashedlines) serves to direct the datum line at an angle (ø₂) to ground thatis greater than the angle (ø₁) generated by the convex outboard wingportion 1312 of FIG. 13. Similarly, in FIG. 15, the convex outboard wingportion 1512 may direct the datum line to an angle (ø₃) that isapproximately 90 degrees away from the ground. Less sound energy isreceived at ground level with increasing angle (ø). The resultinghigh-pressure underwing to freestream low pressure interfaces (1404,1504) illustrated in FIGS. 14 and 15 channel their respective soundpropagating vectors (1410, 1510) at an inclination to the ground andparallel to the ground, respectively.

While various embodiments have been described, it will be apparent tothose of ordinary skill in the art that many more embodiments andimplementations are possible that are within the scope of thisinvention.

What is claimed is:
 1. A method of shockwave mitigation in supersonicvehicles, comprising: generating an earthward propagating wingcompression shockwave from a curved wing; expelling a first supersonicexhaust plume having a first average velocity from an engine, the enginehaving an engine housing; reflecting a majority of the earthwardpropagating wing compression shockwave back towards the curved wing;expelling a bypass exhaust plume having a second average velocityadjacent to the first supersonic exhaust plume, the second averagevelocity being slower than the first average velocity; and inhibitingcoalescence of an engine exhaust plume compression shockwave extendingfrom the first supersonic exhaust plume using the bypass exhaust plume.2. The method of claim 1, wherein the step of reflecting a majority ofthe earthward propagating wing compression shockwave back towards thecurved wing using the engine further comprises reflecting the wingcompression shockwave off of the engine housing.
 3. The method of claim2, further comprising moving the engine housing to meet the wingcompression shockwave.
 4. The method of claim 3, wherein the step ofmoving the engine housing comprises translating the engine along theaxis of freestream air flow about the engine.
 5. The method of claim 2,further comprising: slidably moving the wing relative to a fuselageslidably coupled to the wing; wherein the wing compression shockwave ismoved relative to the engine to meet the engine housing.
 6. The methodof claim 1, wherein the step of reflecting a majority of the earthwardpropagating wing compression shockwave back towards the curved wingfurther comprises: reflecting the wing compression shockwave off of thefirst supersonic exhaust plume.
 7. The method of claim 6 whereinreflecting the wing compression shockwave off of the first supersonicexhaust plume establishes an upward propagating reflected compressionshockwave.
 8. The method of claim 1, wherein the step of reflecting amajority of the earthward propagating wing compression shockwave backtowards the curved wing further comprises: reflecting the wingcompression shockwave off of the engine.
 9. The method of claim 1,wherein the second average velocity is approximately the same velocityas a freestream velocity about the wing.
 10. The method of claim 9,wherein the bypass exhaust plume is expelled from the engine.
 11. Themethod of claim 10, wherein the bypass exhaust plume comprises airsourced from an air source selected from the group consisting of (i)bleed air taps from a compressor in the engine, (ii) bleed air taps atinlet shock ramps disposed at a front of the engine.
 12. The method ofclaim 1, wherein the engine has a first nozzle expelling the firstsupersonic exhaust plume and a second nozzle expelling a bypass exhaustplume that has an average velocity that is slower than an averagevelocity of the first supersonic exhaust plume.
 13. The method of claim1, wherein the wing has a bottom surface shape configured to direct thecompression shockwave toward the engine.
 14. The method of claim 1,wherein the step of generating an earthward propagating wing compressionshockwave from the curved wing comprises propagating a majority of thecompression shockwave toward a rear portion of the engine housing. 15.The method of claim 1, wherein the step of generating a earthwardpropagating wing compression shockwave from the curved wing comprisespropagating substantially all of the wing compression shockwave towardthe engine housing.
 16. The method of claim 1, wherein the step ofgenerating a downward propagating wing compression shockwave from thecurved wing towards the earth comprises propagating substantially all ofthe compression shockwave toward the first supersonic exhaust plume. 17.The method of claim 16, wherein the curved wing has an outboard portionshape selected from the group consisting of straight and upward curving;wherein a high-pressure underwing to freestream low pressure interfacechannels a sound propagating vector at an inclination to the ground andparallel to the ground, respectively.
 18. The method of 1, wherein theengine is selected from the group consisting of a jet engine, turbojetengine, ramjet engine, scramjet engine, high bypass turbojet, variablecycle engine, and adaptive-cycle engine.
 19. The method of claim 1,wherein reflecting a majority of the earthward propagating wingcompression shockwave back towards the curved wing using the enginemeans reflecting less than the entire wing compression shockwave.
 20. Amethod of supersonic thrust generation, comprising: generating a thrustsupersonic exhaust plume having a first average velocity from an engine;and expelling a bypass exhaust plume having a second average velocityfrom the engine, the first average velocity greater than the secondaverage velocity; wherein the bypass exhaust plume inhibits coalescenceof a supersonic exhaust plume compression shockwave extending from thefirst supersonic exhaust plume.
 21. The method of claim 20, wherein thethrust supersonic exhaust plume and bypass exhaust plume aresubstantially aligned when exiting the engine.
 22. The method of 20,wherein the bypass exhaust plume is generated from a source selectedfrom the group consisting of (i) bleed air taps from a compressor in theengine, (ii) bleed air taps at inlet shock ramps disposed at a front ofthe engine.
 23. A method of shock wave mitigation in supersonicvehicles, comprising: generating an earthward propagating wingcompression wave region from a curved wing; expelling a first supersonicexhaust plume having a first average velocity from an engine, the enginehaving an engine housing; translating the engine to expel the firstsupersonic exhaust plume immediately upstream from the earthwardpropagating wing compression wave region; wherein the earthwardpropagating wing compression wave region is inhibited from coalescinginto a compression shockwave by the first supersonic exhaust plume. 24.The method of claim 23, further comprising: expelling a bypass exhaustplume having a second average velocity adjacent to the first supersonicexhaust plume, the second average velocity being slower than the firstaverage velocity; and inhibiting coalescence of an engine exhaust plumecompression shockwave extending from the first supersonic exhaust plumeusing the bypass exhaust plume.